God enlarge Japheth: enlarge translates the causative command form of a verb meaning to extend, increase, or make room for. The sense is that Japheth or his descendants should become numerous and require much space. At the same time Noah is making a play on words. In Hebrew to enlarge is yapat, and “Japheth” is Yepet; see Good News Translation footnote. Revised English Bible translates “May God extend Japheth’s boundaries,” and Good News Translation “… cause Japheth to increase.” Die Bibel im heutigen Deutsch says “and he [God] lets the descendants of Japheth spread out.” We may also say “May God cause Japheth to have many descendants and spread out over the land” or “… and live throughout the land.”
The expression “May God cause…” is actually a wish that God will act, or a prayer or request to God to act in the way referred to. In some languages this will need to be made clear, since there are no forms or aspects of verbs that carry this sense by themselves. For instance, in one language verse 27 begins “This is my prayer, that God will….”
Let him dwell in the tents of Shem: him refers to Japheth, but most likely as the representative of his line of descendants. Dwell translates a verb meaning to “live,” or “settle.” The expression dwell in the tents of is an idiom that is used sometimes of invaders driving their enemies out and taking over their territory. See 1 Chr 5.10; Psa 78.55. In Psa 84.10 the expression is used metaphorically: “I would rather be a doorkeeper in the house of my God than dwell in the tents of wickedness.” See also Psa 120.5. In the context of verses 24-27 dwell in the tents of Shem most likely refers to some form of cooperation or peaceful coexistence between the descendants of the two brothers; Moffatt translates “May he be welcome in the tents of Shem.” Speiser says it is not possible to fit these conditions with any certainty to a historical period in the land of Canaan. Most modern translations only suggest that peaceful conditions prevail. For example, “May his descendants live with the people of Shem” (Good News Translation), “May he live in the camps of Shem” (Biblia Dios Habla Hoy), “May he have his dwelling with Shem” (Bible en français courant). All of these are suitable models to translate. In two Pacific translations this idea of living together in peace is expressed as “… and they [the descendants of Japheth] stay in peace with the descendants of Shem.”
And let Canaan be his slave repeats the refrain for the final time. In some languages the term “also” or a similar term may be required in this context, since this statement is not meant to contradict or change what is stated earlier at the end of verse 26; Canaan is to be the slave of Shem and the slave of Japheth too.
Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Genesis. (UBS Helps for Translators). New York: UBS, 1997. For this and other handbooks for translators see here .